Ford Mustang Service Manual: Component Tests

NOTE: It may be necessary to have the customer ride along or drive the
vehicle to point out the
concern. During the road test, take into consideration the customer's driving
habits and the driving
conditions. The customer's concern just may be an acceptable operating condition
for that vehicle.

The following is a brief overview of each test in the order in which it appears.
A review of this
information helps to quickly identify the most appropriate process necessary to
make a successful
diagnosis. After reviewing this information, select and carry out the
appropriate test(s), proceeding to
the next step of this process.

The Slow Acceleration Test is normally the first test to carry out when
identifying an NVH
concern, especially when a road test with the customer is not possible.

The Heavy Acceleration Test helps to determine if the concern is
torque-related.

The Neutral Coast Down Speed Test helps to determine if the concern is
vehicle speed-related.

The Downshift Speed Test helps to determine if the concern is engine
speed-related.

The Steering Input Test helps to determine how the wheel bearings and
other suspension
components contribute to a vehicle speed-related concern.

The Brake Test helps to identify vibrations or noise that are brake
related.

The Road Test Over Bumps helps isolate a noise that occurs when driving
over a rough or
bumpy surface.

The Engine Run-Up Tests consist of the Neutral Run-Up Test and the
Engine Load Test. These
tests help to determine if the concern is engine speed-related.

The Neutral Run-Up Test is used as a follow-up test to the Downshift
Speed Test when the
concern occurs at idle.

The Engine Load Test helps to identify vibration/noise sensitive to
engine load or torque. It also
helps to reproduce engine speed-related concerns that cannot be duplicated
when carrying out
the Neutral Run-Up Test or the Neutral Coast Down Test.

The Vehicle Cold Soak Procedure helps to identify concerns occurring
during initial start-up and
when an extended time lapse occurs between vehicle usage.

Slow Acceleration Test

To carry out this test, proceed as follows:

Slowly accelerate to the speed where the reported concern occurs. Note
the vehicle speed, the
engine rpm and, if possible, determine the vibration frequency.

Attempt to identify from what part of the vehicle the concern is coming.

Attempt to identify the source of the concern.

Proceed as necessary.

Heavy Acceleration Test

To carry out this test, proceed as follows:

Accelerate hard from 0-64 km/h (0-40 mph).

Decelerate in a lower gear.

The concern is torque related if duplicated while carrying out this
test.

Proceed as necessary.

Neutral Coast Down Speed Test

To carry out this test, proceed as follows:

Drive at a higher rate of speed than where the concern occurred when
carrying out the Slow
Acceleration Test.

Place the transmission in NEUTRAL and coast down past the speed where
the concern occurs.

The concern is vehicle speed-related if duplicated while carrying out
this test. This eliminates
the engine and the torque converter as sources.

If the concern was not duplicated while carrying out this test, carry
out the Downshift Speed
Test to verify if the concern is engine speed related.

Proceed as necessary.

Downshift Speed Test

To carry out this test, proceed as follows:

Shift into a lower gear than the gear used when carrying out the Slow
Acceleration Test.

Drive at the engine rpm where the concern occurs.

The concern is engine speed related if duplicated while carrying out
this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.

If necessary, repeat this test using other gears and NEUTRAL to verify
the results.

Proceed as necessary.

Steering Input Test

To carry out this test, proceed as follows:

Drive at the speed where the concern occurs, while making sweeping turns
in both directions.

If the concern goes away or gets worse, the wheel bearings, hubs,
U-joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.

Proceed as necessary.

Brake Test

To carry out this test, proceed as follows:

Warm the brakes by slowing the vehicle a few times from 80-32 km/h
(50-20 mph) using light
braking applications. At highway speeds of 89-97 km/h (50-60 mph), apply the
brake using a
light pedal force.

Accelerate to 89-97 km/h (55-60 mph).

Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).

A brake vibration noise can be felt in the steering wheel, seat or brake
pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.

Road Test Over Bumps

To carry out this test, proceed as follows:

Drive the vehicle over a bump or rough surface one wheel at a time to
determine if the noise is
coming from the front or the back and the left or the right side of the
vehicle.

Proceed as necessary.

Neutral Engine Run-Up (NERU) Test

To carry out this test, proceed as follows:

Install a tachometer.

Increase the engine rpm up from an idle to approximately 4000 rpm while
in PARK on front
wheel drive vehicles with automatic transmissions, or NEUTRAL for all other
vehicles. Note the
engine rpm and, if possible, determine the vibration frequency.

Attempt to identify what part of the vehicle the concern is coming from.

Attempt to identify the source of the concern.

Proceed as necessary.

Drive Engine Run-Up (DERU) Load Test

To carry out this test, proceed as follows:

WARNING: Block the front and rear wheels, and apply the parking
brake and the
service brake, or injury to personnel can result.

CAUTION: Do not carry out the Engine Load Test for more than five seconds or
damage to the transmission or transaxle can result.

Block the front and rear wheels.

Apply the parking brake and the service brake.

Install a tachometer.

Shift the transmission into DRIVE, and increase and decrease the engine
rpm between an idle
to approximately 2000 rpm. Note the engine rpm and, if possible, determine
the vibration
frequency.

Repeat the test in REVERSE.

If the vibration/noise is duplicated when carrying out this test,
inspect the engine and
transmission or transaxle mounts.

If the concern is definitely engine speed-related, carry out the Engine
Accessory Test to narrow
down the source.

Proceed as necessary.

Engine Accessory Test

To carry out this test, proceed as follows:

WARNING: Block the front and rear wheels, and apply the parking
brake and the
service brake, or injury to personnel can result.

CAUTION: Limit engine running time to one minute or less with belts removed
or
serious engine damage will result.

NOTE: A serpentine drive belt decreases the usefulness of this
test. In these cases, use a
vibration analyzer, such as the VA, to pinpoint accessory vibrations. An
electronic listening
device, such as an EngineEAR, will also help to identify noises from
specific accessories.

Remove the accessory drive belts.

Increase the engine rpm to where the concern occurs.

If the vibration/noise is duplicated when carrying out this test, the
belts and accessories are not
sources.

If the vibration/noise was not duplicated when carrying out this test,
install each accessory belt,
one at a time, to locate the source.

Vehicle Cold Soak Procedure

To carry out this procedure, proceed as follows:

Test preparations include matching customer conditions (if known). If
not known, document the
test conditions: gear selection and engine rpm. Monitor the vibration/noise
duration with a watch
for up to three minutes.

Park the vehicle where testing will occur. The vehicle must remain at or
below the concern
temperature (if known) for 6-8 hours.

Before starting the engine, conduct a visual inspection under the hood.

Turn the key on, but do not start the engine. Listen for the fuel pump,
anti-lock brake system
(ABS) and air suspension system noises.

Start the engine.

CAUTION: Never probe moving parts.

Isolate the vibration/noise by carefully listening. Move around the
vehicle while listening to find
the general location of the vibration/noise. Then, search for a more precise
location by using a
stethoscope or EngineEAR.

GO to Symptom Chart - Idle Noise/Vibration to assist with the diagnosis.

6: Check OASIS/TSBs/Repair History

After verifying the customer concern, check for OASIS reports, TSBs and the
vehicle repair history for
related concerns. If information relating to a diagnosis/repair is found, carry
out the procedure(s)
specified in that information.

If no information is available from these sources, carry out the vehicle
preliminary inspection to
eliminate any obvious faults.

7: Diagnostic Procedure

Qualifying the concern by the particular sensation present can help narrow
down the concern. Always
use the "symptom" to "system" to "component" to "cause" diagnosis technique.
This diagnostic method
divides the problem into related areas to correct the customer concern.

Verify the "symptom".

Determine which "system(s)" can cause the "symptom".

If a vibration concern is vehicle speed related, the tire and wheel
rpm/frequency or
driveshaft frequency should be calculated.

If a vibration concern is engine speed related, the engine, engine
accessory or engine
firing frequencies should be calculated.

After determining the "system", use the diagnostic tools to identify the
worn or damaged
"components".

After identifying the "components", try to find the "cause" of the
failure.

Once the concern is narrowed down to a symptom/condition, proceed to NVH
Condition and Symptom
Categories.

Road Test
NOTE: It may be necessary to have the customer ride along or drive the
vehicle to point out the
concern. During the road test, take into consideration the customer's driving
habits and the ...

Noise, Vibration and Harshness (NVH) (Description and Operation)
Noise is any undesirable sound, usually unpleasant in nature. Vibration is
any motion, shaking or
trembling, that can be felt or seen ...

Other materials:

Display mode
You can choose to turn your screen on or off and if you would like to view the
status bars on the top and bottom of the screen. Press DISP to see the options.
Display Mode Voice Commands
The following voice commands are available in display mode.
If you ...

Closing the convertible top
Note: The convertible top will not operate unless the vehicle is stationary
or traveling under 3 mph (5 kmh).
Note: Make sure that the latch handles are pulled down and in the fully
opened position before the top makes contact with the windshield header. ...

Steering Column Shaft
Steering Column (Description and Operation)
NOTE: All fasteners are important because they can affect the
performance of vital parts and systems.
Incorrect installation of the fasteners can result in major repair expenses.
They must be installed ...